In the process of assembly and debugging, the vibration generated by the rotating movement of the machine is inevitable. The vibration generated by the machine will cause certain harm to the normal use of the machine tool. It will reduce the working performance of the machine tool, or even fail to work at all. It will also cause accelerated wear and fatigue of some parts and reduce the service life of the machine tool. When some abnormal vibration occurs, measures must be taken to eliminate it in order to ensure the safe operation of the machine tool. During the assembly and commissioning of gantry machining center, the vibration of lead screw is often encountered. In addition to the improper setting and selection of system electrical parameters, there are also some mechanical reasons, mainly in the following aspects:

一、絲杠安裝因素

1、 Lead screw installation factors

現(xiàn)龍門加工中 心包括數(shù)控機(jī)床的傳動(dòng)絲杠都是滾珠絲杠，而且傳動(dòng)精度較高，同時(shí)對(duì)我們裝配的安裝精度也有較高的要求。絲杠傳動(dòng)結(jié)構(gòu)主要由絲杠本身、絲杠螺母、絲杠座（也叫軸承座）、絲杠軸承、鎖緊螺母、聯(lián)軸器、伺服電機(jī)等組成。在安裝過程中，必 須保證絲杠軸心線與運(yùn)動(dòng)導(dǎo)軌基準(zhǔn)面平行，如果安裝誤差較大時(shí)，拖板在運(yùn)動(dòng)過程中會(huì)使絲杠產(chǎn)生彎曲變形，絲杠旋轉(zhuǎn)受力不均勻，進(jìn)而產(chǎn)生振動(dòng)現(xiàn)象。

At present, the transmission screws of gantry machining center including CNC machine tools are ball screws, and the transmission accuracy is high. At the same time, it also has high requirements for the installation accuracy of our assembly. The lead screw transmission structure is mainly composed of lead screw itself, lead screw nut, lead screw seat (also known as bearing seat), lead screw bearing, lock nut, coupling, servo motor, etc. During installation, it must be ensured that the axis line of the lead screw is parallel to the datum plane of the moving guide rail. If the installation error is large, the carriage will bend and deform the lead screw during movement, and the rotation force of the lead screw is uneven, resulting in vibration.

二、絲杠螺母與拖板連接安裝因素

2、 Installation factors of connection between lead screw nut and carriage

在絲杠螺母與拖板連接的安裝過程中，有時(shí)會(huì)由于拖板端面加工原因，造成絲杠螺母上的螺絲孔與拖板結(jié)合面的安裝孔互相干涉，或者安裝面與基準(zhǔn)（導(dǎo)軌）面不垂直，也就是安裝面與絲杠螺母結(jié)合面不平行，導(dǎo)致絲杠螺母緊固螺釘擰緊后迫使絲杠產(chǎn)生變形，發(fā)生振動(dòng)現(xiàn)象。

During the installation of the connection between the lead screw nut and the carriage, sometimes the screw hole on the lead screw nut interferes with the installation hole on the joint surface of the carriage due to the processing of the end face of the carriage, or the installation surface is not perpendicular to the reference (guide rail) surface, that is, the installation surface is not parallel to the joint surface of the lead screw nut, resulting in the deformation of the lead screw after the fastening screw of the lead screw nut is tightened, Vibration occurs.

三、聯(lián)軸器的安裝因素

3、 Installation factors of coupling

電機(jī)帶動(dòng)絲杠轉(zhuǎn)動(dòng)是通過彈性聯(lián)軸器連接的，在這部分的安裝過程中，必 須保證絲杠端部的徑向跳動(dòng)誤差符合設(shè)計(jì)要求，其次要保證電機(jī)安裝面與絲杠軸心線垂直，電機(jī)旋轉(zhuǎn)軸心線與絲杠軸心線重合，一般由設(shè)計(jì)要求定位孔保證。較后，均勻地用力矩扳手?jǐn)Q緊聯(lián)軸器上脹套壓蓋的緊固螺釘，如此三個(gè)條件未滿足，絲杠和聯(lián)軸器就會(huì)產(chǎn)生振動(dòng)。

The rotation of the lead screw driven by the motor is connected through the elastic coupling. In the installation process of this part, firstly, it must ensure that the radial runout error at the end of the lead screw meets the design requirements. Secondly, it must ensure that the installation surface of the motor is perpendicular to the axis line of the lead screw, and the rotation axis line of the motor coincides with the axis line of the lead screw, which is generally guaranteed by the positioning hole required by the design. Later, tighten the fastening screws of the expansion sleeve gland on the coupling evenly with a torque wrench. If the three conditions are not met, the lead screw and coupling will vibrate.

四、絲杠軸向間隙的因素

4、 Factors affecting axial clearance of lead screw

在拖板運(yùn)動(dòng)過程中，如果絲杠的軸向間隙過大，也會(huì)產(chǎn)生振動(dòng)現(xiàn)象，包括拖板爬行現(xiàn)象。這是因?yàn)閿?shù)控軸本身帶有光柵尺，在光柵尺生效情況下，根據(jù)光柵信號(hào)的反饋，伺服電機(jī)會(huì)不斷正反旋轉(zhuǎn)糾正拖板位置，時(shí)快時(shí)慢，速度不均勻而產(chǎn)生振動(dòng)。

During the movement of the carriage, if the axial clearance of the lead screw is too large, it will also produce vibration, including the crawling of the carriage. This is because the NC axis itself has a grating ruler. When the grating ruler takes effect, according to the feedback of the grating signal, the servo motor will continuously rotate forward and backward to correct the carriage position, which is fast and slow, and the speed is uneven, resulting in vibration.